Since the late 1980s, endoscopic surgery has been growing in popularity at a very high rate. More and more, procedures which have customarily been performed by making large incisions in the patient's body are now being performed by "minimally invasive" or endoscopic methods. It has been estimated that by the year 2000, 40 to 50 percent of all surgeries will be done endoscopically.
Endoscope is the generic term for a viewing tube which can be inserted into the body. In endoscopic surgery, the surgeon makes a hole or portal in the patient's body with a sharp punch-like device called a trocar which is inserted through a sleeve or cannula. The trocar is then removed, leaving the cannula in the portal. The surgeon then inserts desired instruments into the body via the cannula. The instruments generally include a light source, a TV camera, and surgical tools such as scissors, graspers, dissectors and the like.
With the increase in endoscopic procedures has come an increase in demand for surgical instruments adapted for endoscopic applications. Specifically, the instruments must be small in cross-section to minimize trauma to the body. Also, they must be controllable from outside the body through an extended length. Precise control of instrument operation is imperative as any undesirable movement of the instrument during surgery can have disastrous results.